Question

As you see below; how can I implement fx.ftf_validitystartdate= … this lines value since oracle does not allow me to do it like this below
.

    select * from  acc_accounts acc
    join kp_paramcore p on
    acc.account_no = p.accountnum
    acc.suffix = p.suffixc
         LEFT JOIN ftf_rates fx
              ON p.maturestart = fx.ftf_vadealtsinir
             AND p.maturefinish = fx.ftf_vadeustsinir
             AND fx.statusrec = 'A'
             AND fx.currencycode = acc.currencsw_kod
             AND fx.status= 'A' 
  and  fx.ftf_validitystartdate= (SELECT MAX(ff.ftf_validitystartdate)
                                               FROM ftf_rates ff
                                              WHERE ff.status = 'A'
                                                AND ff.statusrec = 'A'
                                                AND v_CurrentDate BETWEEN ff.systemstartdate AND ff.systemfinishdate                                            AND ff.currencycode = acc.currencsw_kod
    )

Answer 1

I publish the workaround with CTE and tested only in Oracle 11g.

To make test I create this schema:

create table t_a ( a int );
create table t_b ( a int);
create table t_c ( a int);

insert into t_a values (1);
insert into t_a values (2);
insert into t_a values (3);

insert into t_b values (1);
insert into t_b values (2);
insert into t_b values (3);

insert into t_c values (1);
insert into t_c values (2);
insert into t_c values (3);

At this time I force error with this query:

select * 
from t_a
left outer join t_b
  on t_a.a = t_b.a and
     t_b.a = ( select max( a )
             from t_c);

And now I rewrite query with CTE:

with cte (a ) as (
   select a
   from t_b
   where t_b.a = ( select min( a )
             from t_c)
)
select * 
from t_a
left outer join cte
  on t_a.a = cte.a;

This second query returns right results.

I rewrite your query with CTE:

with CTE as (
   select * from ftf_rates 
   where ftf_validitystartdate= (SELECT MAX(ff.ftf_validitystartdate)
                                 FROM ftf_rates ff
                                 WHERE ff.status = 'A'
                                      AND ff.statusrec = 'A'
                                      AND v_CurrentDate BETWEEN ff.systemstartdate 
                                      AND ff.systemfinishdate                   
                                      AND ff.currencycode = acc.currencsw_kod )

)
    select * from  acc_accounts acc
    join kp_paramcore p on
    acc.account_no = p.accountnum
    acc.suffix = p.suffixc
         LEFT JOIN CTE fx
              ON p.maturestart = fx.ftf_vadealtsinir
             AND p.maturefinish = fx.ftf_vadeustsinir
             AND fx.statusrec = 'A'
             AND fx.currencycode = acc.currencsw_kod
             AND fx.status= 'A' 

Notice, only tested in Oracle 11g. See @a_horse_with_no_name coment:

@danihp: CTEs were available long before Oracle 11g (I think they were
introducted in 9.1 maybe even earlier – but they are definitely
available in 10.x). 11.2 introduced recursive CTEs which is not needed
in this case. –